The T-65D-A1 X-wing Starfighter was introduced a year after the unveiling of the T-65AC4 X-wing model and is the result of a long and (some would say) relatively fruitless research project by Incom.
The T-65D-A1 is the first, and so far only, X-wing variant to include a computer system that integrates all the functions of an astromech droid, meaning that the droid is no longer necessary. As such, the T-65D-A1 X-wing is easily identified by the lack of an astromech socket. The computer system is accessible from the cockpit, so that the pilot can have more control over the customizable options available during flight and combat.
Upon introduction, however, would-be terrorists equipped a hidden explosive detonator in each computer that would be fitted to a fighter, activated by a certain set of commands. This grounded the New Republic X-wing fleet for a while and considerably ruined the T-65D-A1 refit. Even after the situation was resolved, many pilots, some quite popular and influential, complained about missing their astromech "co-pilots" to such a degree that the T-65D-A1 never gained widespread popularity in the New Republic fleet.